Photovoltaics (PV) have the potential to produce electricity on a large scale and thereby help reducing the greenhouse gas emissions. Commonly seen examples of PV are large-scale solar farms or roof top modules based on Si PV. Supplementary to these examples, solar cells may also be integrated in buildings, cars, inhouse devices etc. For these latter options, highly efficient thin film (TF) PV can be used.
One way to achieve highly efficient TF PV devices is to stack cells with different band gaps on top of each other. In this way both the photon energy as the number of photons in the solar spectrum are optimally used. At Energyville we are working on so-called tandem structures in which a high band gap solar cell on top absorbs the UV and visible light, leading to high voltage output and a low band gap cell at the bottom absorbs the NIR light. As low band gap material CuIn(Ga)Se2 (CIS) with a band gap of 1 eV is used. The aim is to absorb as much light as possible of the near infrared part. However, these long wavelengths are badly absorbed and for this thesis we want to look into options to increase the path length for the unabsorbed NIR light. To do this we will adapt the back contact in such a way that it scatters the unabsorbed NIR light back into the solar cell. We will try various commonly used light management techniques like scattering nanoparticles and/or layers that can be made from metals and/or dielectrics. These structures will be optically characterized for their scattering properties. The CIS layers will be deposited in Eindhoven (solliance) with a co-evaporation technique on top of these structures and further processed into solar cells.
The student should have interest in solar cells, optics and device physics. The work is experimental as focus will be on making various back contacts by adding metallic/dielectric layers and anneal them at elevated temperature. Layers that show good scattering properties (for NIR wavelengths) will be used for solar cells production. The cells will be electrically and optically characterized for their optical enhancement.
Type of project: Internship, Thesis, Combination of internship and thesis
Required degree: Master of Engineering Technology, Master of Science, Master of Engineering Science
Required background: Nanoscience & Nanotechnology
Imec allowance will be provided for students studying at a non-Belgian university.